Package substrate with high-density interconnect layer having pillar and via connections for fan out scaling

ABSTRACT

Integrated circuit package substrates with high-density interconnect architecture for scaling high-density routing, as well as related structures, devices, and methods, are generally presented. More specifically, integrated circuit package substrates with fan out routing based on a high-density interconnect layer that may include pillars and vias, and integrated cavities for die attachment are presented. Additionally, integrated circuit package substrates with self-aligned pillars and vias formed on the high-density interconnect layer as well as related methods are presented.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/347,188 filed May 2, 2019 and entitled “WITH HIGH-DENSITYINTERCONNECT LAYER HAVING PILLAR AND VIA CONNECTIONS FOR FAN OUTSCALING,” which is a national stage application under 35 U.S.C. § 371 ofPCT International Application Serial No. PCT/US2016/069377 filed on Dec.30, 2016 and entitled “PACKAGE SUBSTRATE WITH HIGH-DENSITY INTERCONNECTLAYER HAVING PILLAR AND VIA CONNECTIONS FOR FAN OUT SCALING,” all ofwhich are hereby incorporated by reference in their entirety.

FIELD

Embodiments relate to manufacturing of semiconductor devices. Moreparticularly, the embodiments relate to a package substrate having ahigh-density interconnect layer with pillars and vias for scaling ofinterconnects as well as integrated cavities for die attachment.

BACKGROUND

Semiconductor dies are routinely connected to larger circuit boards suchas motherboards and other types of printed circuit boards (PCBs) via apackage substrate. A package substrate typically has two sets ofconnection points, a first set for connection to the die or multipledies and a second less densely-packed set for connection to the PCB. Apackage substrate generally consists of an alternating sequence of aplurality of organic insulation or dielectric layers and a plurality ofpatterned electrically conductive layers forming traces between theinsulation layers. Electrically conductive vias, which extend throughthe insulation layers, electrically interconnect the conductive layers.Continued advancements in integrated circuit technology have resulted inthe need for package substrates having higher routing density.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments described herein illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which likereferences indicate similar features. The following figures areillustrative, and other processing techniques or stages can be used inaccordance with the subject matter described herein. Furthermore, someconventional details have been omitted so as not to obscure from theinventive concepts described herein.

FIGS. 1-12 are cross-sectional side views of various stages in themanufacture of a package substrate having a high-density interconnectlayer for scaling interconnects, in accordance with various embodiments.

FIGS. 13A-B are a flow diagram of an example method of manufacturing apackage substrate including a high-density interconnect layer forscaling interconnects, in accordance with various embodiments.

FIGS. 14-20 are cross-sectional side views of various stages in themanufacture of a package substrate having a high-density interconnectlayer for scaling interconnects and an integrated cavity, in accordancewith various embodiments.

FIG. 21 is a flow diagram of an example method of manufacturing apackage substrate including a high-density interconnect layer forscaling interconnects and an integrated cavity, in accordance withvarious embodiments.

FIG. 22A is a plan view of a carrier layer with foil layers formed overthe surfaces in an example method of manufacturing a self-aligned via ina package substrate including a high-density interconnect layer, inaccordance with various embodiments.

FIGS. 22B-C are two corresponding cross-sectional views of a carrierlayer with foil layers formed over the surfaces, in accordance withvarious embodiments.

FIG. 23A is a plan view of the carrier layer after a first photoresistlayer has been patterned over the surfaces, in accordance with variousembodiments.

FIGS. 23B-C are two corresponding cross-sectional views of the carrierlayer after a first photoresist layer has been patterned over thesurfaces, in accordance with various embodiments.

FIG. 24A is a plan view of the carrier layer after a second photoresistlayer has been patterned over the surfaces, in accordance with variousembodiments.

FIGS. 24B-C are two corresponding cross-sectional views of the carrierlayer after a second photoresist layer has been patterned over thesurfaces, in accordance with various embodiments.

FIG. 25A is a plan view of the carrier layer after exposed metalportions have been etched, in accordance with various embodiments.

FIGS. 25B-C are two corresponding cross-sectional views of the carrierlayer after exposed metal portions have been etched, in accordance withvarious embodiments.

FIG. 26A is a plan view of the carrier layer after metal has been platedto fill the vias, in accordance with various embodiments.

FIGS. 26B-C are two corresponding cross-sectional views of the carrierlayer after metal has been plated to fill the vias, in accordance withvarious embodiments.

FIG. 27A is a plan view of the carrier layer after the secondphotoresist layer has been removed, in accordance with variousembodiments.

FIGS. 27B-C are two corresponding cross-sectional views of the carrierlayer after the second photoresist layer has been removed, in accordancewith various embodiments.

FIG. 28 is a flow diagram of an example method of forming a self-alignedvia in a package substrate including a high-density interconnect layeras shown in FIGS. 22-28, in accordance with various embodiments.

FIGS. 29A and 29B are top views of a wafer and dies that may be usedwith any of the embodiments of the IC structures disclosed herein.

FIG. 30 is a cross-sectional side view of an IC device that may be usedwith any of the embodiments of the IC structures disclosed herein.

FIG. 31 is a cross-sectional side view of an IC device assembly that mayinclude any of the embodiments of the IC structures disclosed herein.

FIG. 32 is a block diagram of an example computing device that mayinclude any of the embodiments of the IC structures disclosed herein.

DETAILED DESCRIPTION

Integrated circuit package substrates with high-density interconnectarchitecture for scaling routing, as well as related structures,devices, and methods, are generally presented. More specifically,integrated circuit package substrates with fan out routing based on ahigh-density interconnect layer that include pillars and vias, andintegrated cavities for die attachment are presented. Additionally,integrated circuit package substrates with self-aligned pillars and viasas well as related methods are presented.

In the following description, numerous details are discussed to providea more thorough explanation of embodiments of the present disclosure. Itwill be apparent, however, to one skilled in the art, that embodimentsof the present disclosure may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form, rather than in detail, in order to avoidobscuring embodiments of the present disclosure.

Throughout the specification, and in the claims, the term “connected”means a direct connection, such as electrical, mechanical, or magneticconnection between the things that are connected, without anyintermediary devices. The term “coupled” means a direct or indirectconnection, such as a direct electrical, mechanical, or magneticconnection between the things that are connected or an indirectconnection, through one or more passive or active intermediary devices.The term “circuit” or “module” may refer to one or more passive and/oractive components that are arranged to cooperate with one another toprovide a desired function. The term “signal” may refer to at least onecurrent signal, voltage signal, magnetic signal, or data/clock signal.The meaning of “a,” “an,” and “the” include plural references. Themeaning of “in” includes “in” and “on.”

Unless otherwise specified the use of the ordinal adjectives “first,”“second,” and “third,” etc., to describe a common object, merelyindicate that different instances of like objects are being referred to,and are not intended to imply that the objects so described must be in agiven sequence, either temporally, spatially, in ranking or in any othermanner.

For the purposes of the present disclosure, phrases “A and/or B” and “Aor B” mean (A), (B), or (A and B). For the purposes of the presentdisclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B),(A and C), (B and C), or (A, B and C). The terms “left,” “right,”“front,” “back,” “top,” “bottom,” “over,” “under,” “on,” and the like inthe description and in the claims, if any, are used for descriptivepurposes and not necessarily for describing permanent relativepositions.

Package substrates for multi-chip packaging (MCP) require significantlyhigh-density input/output (IO) routing as well as varied IO density fordie attachment. The IO density of a substrate may be physicallyconstrained by other elements within the substrate, including via size,line/space pitch (L/S), bump pitch, via-to-pad alignment, pad-to-viaalignment, and material (e.g. resist and thin dielectric material)properties. For example, using a known process to achieve a 110 micron(um) bump pitch results in a density of less than 20 IO/mm/layer wherevias have a diameter of 50 um, a 10/10 um L/S, and 15 um alignment. Asused herein, bump pitch refers to the distance between bumps (i.e.,center point to center point). As used herein, “line space” and “L/S”are used interchangeably and refer to the width of the conductive tracefollowed by the space from the edge of one conductive trace to the edgeof the next conductive trace. As used herein, “line space pitch” refersto the summation of the line and space values.

As described herein, very high-density interconnects or routing may be asingle layer or multiple layers where the conductive traces in multiplelayers are connected by vias, and refers to an input and output (IO)density associated with a substrate layer, where the IO density isgreater than 100 IO density (i.e., 100 IO/mm/layer). As used herein,“high-density layer”, “high-density interconnects”, and “high-densityinterconnect layer” may be used interchangeably. High-densityinterconnect layers may enable communication between dies on the sameintegrated circuit package by conductively connecting or coupling thedies.

As is known in the art, the term “interconnect” (also sometimes referredto as a trench, a line, or a trace) is used to describe an electricallyconductive line isolated by a layer typically comprising an interlayerdielectric material that is provided within the plane of an IC chip.Such interconnects are typically stacked into several levels with alayer of dielectric in between the metal layers to form a packagesubstrate, an interposer, or other integrated circuit interconnectstructures. This stack of dielectric and conductive layers may bereferred to herein as the “package substrate”, “build up layer”, or“package substrate build up layer”, and may be formed using build upprocesses that are known in the art. As is also known in the art, theterm “via” is used to describe an electrically conductive element thatelectrically interconnects two or more metal trenches of differentlevels. Vias are provided substantially perpendicularly to the plane ofan IC chip. A via may interconnect two metal trenches in adjacent levelsor two metal trenches in levels that are not adjacent to one another. Asis known in the art, the terms lines, trenches, and vias are commonlyassociated with the features that are used to form metal interconnects.As used herein, the terms “line”, “trace”, “interconnect”, and “trench”may be used interchangeably.

A high-density interconnect layer (e.g., 2/2 micron L/S) may be used tofan out routing for bump pitch (BP) dimensions that are too dense forcurrent standard substrate technology (for example, a 40 um BP may befanned out to a 100 um BP). The high-density layer may be used with viaand pillar formation to enable high routing density (e.g., 2/2 um L/Sand 14 um Pad) on a single layer. As used herein, pillar refers to aconductive vertical structure formed on the active side of thehigh-density interconnect layer that connects the high-density layer toa die or other device. As used herein, via refers to a conductivevertical structure formed on the back side of the high-densityinterconnect layer that connects the high-density layer to the packagesubstrate. Also, as used herein, via may refer to a via formed in thepackage substrate, however, the following description as well as contextwill distinguish a via formed on a high-density interconnect layer froma via formed in the package substrate layer, as necessary. Thehigh-density interconnect layer may be used as the starting layer forthe fan out routing, which may be performed in multiple layers of apackage substrate in accordance with standard design rules (e.g. 10/10um L/S and 80 um pad). In some embodiments, the fan out routing mayinclude an integrated cavity for the attachment of die with a coarserbump pitch to reduce both substrate x/y dimensions and warpage risks. Insome embodiments, an embedded trace (ETS) layer is an example of apackage substrate described herein having a high-density interconnectlayer with via and pillar formation as the starting layer for the fanout routing. In some embodiments, the I/O range of the high-densityinterconnect layer is between 100-1000 I/O/mm/layer. In someembodiments, the pad size of the high-density interconnect layer may be1 um-24 um. In some embodiments, the bump pitch of the high-densityinterconnect layer may be 10 um-80 um.

FIGS. 1-12 are cross-sectional side views of various stages in themanufacture of a package substrate of that includes a high-densityinterconnect layer for scaling interconnects, in accordance with variousembodiments. FIGS. 1-12 illustrate substrates being formed on both sidesof the carrier, as such, all descriptions apply to both sides of thecarrier.

FIG. 1 illustrates assembly 100 including a carrier or carrier substrate102, a first metal layer 104, a second metal layer 106, and a seed layer108. Carrier 102 maybe rigid to provide a flat and stable surface tofacilitate tight design rules (e.g., 4 um pitch copper patterns, etc.)during manufacturing. Carrier 102 may be of any suitable material, suchas stainless steel, glass, silicon, fiber-glass reinforced epoxy, amongothers. Carrier 102 may be temporary and may include a release layeronto which the first metal layer 104 may be deposited. The first metallayer 104 may be a foil layer and may be any suitable metal, preferably,copper. The first metal layer 104 may be laminated on the surfaces ofthe carrier 102, plated, or otherwise deposited using any suitablemeans. In certain examples, the surfaces of the carrier 102 may includethe first metal layer 104, such that the carrier may be referred to as anickel-clad carrier when the first metal layer 104 is nickel, or may bereferred to as a copper-clad carrier when the first metal layer 104 iscopper, etc. The second metal layer 106 may be plated or laminated ontothe first metal layer 104, and may be any suitable metal that isdifferent from the first metal layer, preferably, nickel. Nickel andcopper are advantageous first and second metals because they are easilydeposited, and each have selective etches to remove one metal whileleaving the other. In other examples, the first and second metals may beswitched, or other metals may be used in accordance with theseprinciples. The second metal layer may be plated or laminated on top ofthe first metal layer to facilitate self-aligned pillar formation asdescribed below with reference to FIGS. 22-28. In some embodiments, thesecond metal layer thickness may be between 3 um and 20 um. The seedlayer 108 may be deposited on the second metal layer 106 and may be anysuitable material, preferably, copper. In some embodiments, the seedlayer 108 maybe plated using an electroless process. In someembodiments, the seed layer thickness may be less than 1 um.

FIG. 2 illustrates assembly 200 subsequent to applying a photoresist 112to assembly 100 and lithographically patterning the high-density layer110. Before patterning, the carrier may be planarized by grinding,lapping or chemical mechanical polishing to reduce surface roughness andcomply with flatness requirements for photolithography. Photoresist 112may be a liquid or dry film type. The photoresist 112 may be applied tothe carrier 102 and the high-density layer may be lithographicallypatterned. After patterning, metal traces may be plated in regions wherethe photoresist was removed. The metal traces 110 maybe any suitablemetal, preferably, copper.

FIG. 3 illustrates assembly 300 subsequent to pillar formation 114 onthe high-density layer in assembly 200. In some embodiments, pillars maybe formed by chemically etching using a dry or wet etching process, orany other suitable process. In some embodiments, the pillars are formedusing self-aligned pillar formation. As used herein, a self-alignedpillar refers to a conductive vertical structure that is formed by aself-aligned pillar formation process described below that connects thehigh-density layer to a die or other device. The pillar is formed on the“active side” of the high-density interconnect layer, which becomes theactive side of the package substrate.

FIG. 4 illustrates an assembly 400 subsequent to via formation 116 onthe high-density layer in assembly 300. In some embodiments, the viasare formed using self-aligned via formation. As used herein, aself-aligned via refers to a conductive vertical structure that isformed using a self-aligned via formation process described below andconnects the high-density layer to the package substrate. The via isformed on the “back side” of the high-density interconnect layer, whichbecomes the back side of the package substrate. For example, a semiadditive process (SAP) process, a subtractive process, or other knownprocess, may be used to form the package substrate layer. As describedbelow with reference to FIGS. 22-28, for self-aligned via and pillarformation, the photoresist remains on the surface as part of theself-alignment process as the first photoresist layer. Once theself-aligned pillars 114 and vias 116 are formed, photoresist 112 may beremoved.

The conductive vias and pillars may be formed of one or more conductivematerials, such as a metal (e.g., copper). Although the conductive viasand pillars are shown in the figures as having substantially parallelsidewalls, they may have any profile (e.g., as dictated by themanufacturing operations used to form them). For example, in someembodiments, the conductive vias and pillars may be tapered towards thefront side or the back side. In some embodiments, the width (e.g., thediameter) may differ along the length of the conductive pathway, whereone portion may be wider (e.g., have a larger diameter) than anotherportion. Although the vias and pillars may be any suitable size, in someembodiments, the self-aligned vias may have a diameter of approximately2 um-10 um, and the self-aligned pillars may have a diameter ofapproximately 2-20 um and a bump pitch of 10 um-80 um.

FIG. 5 illustrates assembly 500 subsequent to removing the photoresist112 and, optionally, treating the exposed copper with an adhesionpromoter 118. The adhesion promoter 118 may be a roughening type, achemical type or a dry type, for example, silicon nitride deposited byplasma-enhanced chemical vapor deposition (PECVD). An adhesion promotermay be disposed between any dielectric material and any conductivematerial to promote adhesion between the materials.

FIG. 6 illustrates assembly 600 subsequent to laminating dielectric 120on the high-density/via layer in assembly 500. Dielectric layers may beformed using any suitable process, such as lamination or slit coatingand curing, and with any suitable material. Examples of dielectricmaterials that may be used include, but are not limited to, epoxy-basedmaterials/films, ceramic/silica filled epoxide films, polyimide films,filled polyimide films, other organic materials, and other inorganicdielectric materials known from semiconductor processing as well assilicon dioxide (SiO₂), carbon doped oxide (CDO), silicon nitride,organic polymers such as perfluorocyclobutane orpolytetrafluoroethylene, fluorosilicate glass (FSG), and organosilicatessuch as silsesquioxane, siloxane, or organosilicate glass (OSG). In someembodiments, dielectric layers may be formed to a thickness that willcompletely cover a top surface of the one or more vias to account foruneven surfaces. In some embodiments, the thickness of dielectric layersmay be minimized to reduce the etching time required to expose the oneor more vias in a subsequent processing operation. In some embodiments,dielectric layer thickness may be 3 um-30 um.

FIG. 7 illustrates assembly 700 subsequent to revealing the top surfaceof the vias 122 in assembly 600. The top surface of the vias 122 may berevealed by planarization, for example, grinding, lapping or chemicalmechanical polishing (CMP), or by etching, including wet or dry etching.

FIG. 8 illustrates assembly 800 subsequent to beginning the packagesubstrate build up process (e.g., SAP) by depositing patterned metallayer 124 on assembly 700. As illustrated, conductive material isdeposited into openings formed by the patterned photoresist layer toform traces 124, and pads 125.

FIG. 9 illustrates assembly 900 subsequent to laminating dielectriclayer 126 and drilling via openings 128. The metal layer 124 may be anytype of conductive metal, preferably, copper, and may be deposited usingany suitable process, such as electrolytic plating. In some embodiments,the metal layer 124 may have a thickness of 10 um-20 um. Conductivestructures may be formed using any suitable method, includinglithography and electrolytic plating, and may include one or morelayers. Conductive vias 128, lines 124, and pads 125 may be formed fromany suitable conductive material, for example, copper, aluminum (Al),gold (Au), silver (Ag) and or alloys thereof. In some embodiments of theinvention, the metal used for interconnects is copper or an alloy ofcopper. Preferably, conductive interconnects are copper (Cu).

FIG. 10 illustrates assembly 1000 subsequent to continuing the build upprocess as shown in FIGS. 8 and 9 to build additional trace layersconnected by vias on assembly 900 to form the package substrate. In FIG.10, substrate formation is still being performed on both sides of thecarrier, however, for a clearer illustration, the bottom side has beenomitted from the figure. After the build up process is finished, solderresist 136 is applied on the back side to form regions 134 where soldermay be applied for attachment to a circuit board. The back side of thepackage substrate bump pitch may be any suitable value, for example,between 200 um-1000 um. The I/O of the package substrate may be anysuitable value, for example, between 15-60 I/O/mm/layer.

FIG. 11 illustrates assembly 1100, which is assembly 1000 subsequent toseparating or removing the assembly from the carrier. Followingseparation, the substrate assembly may be significantly less rigid and,in some embodiments, may have a temporary carrier attached on the solderresist side 136, which is the back side. Once the carrier is removed,the first metal layer may be removed, for example, by etching, and aselective metal etch may be used to remove the second metal layer whilemaintaining the integrity of the pillars 138.

FIG. 12 illustrates assembly 1200 subsequent to depositing an adhesionpromoter, laminating dielectric, and exposing the top surface of thepillars on the active side of assembly 1000 for die attachment.Dielectric lamination, via formation, and via exposure may be performedas described previously for the high-density layer in FIGS. 6 and 7. Insome embodiments, a surface finish 140, 142 may be applied, such as anelectroless metal or patterned copper to enlarge the available metalarea for die attachment. In some embodiments, assembly may be performedon the exposed copper with the surface protected by a thin surfacefinish, such as Organic Solderability Preservative (OSP) or immersiongold (Au).

Dielectric layers may be formed with any suitable process, such aslamination or slit coating and curing, and with any suitable material,such as epoxy with silica. In some embodiments, dielectric layers areformed to a thickness that will completely cover a top surface of theone or more vias to account for uneven surfaces. In some embodiments,the thickness of dielectric layers may be minimized to reduce theetching time required to expose the one or more vias in a subsequentprocessing operation.

Photoresist layers may be formed with any suitable process, such aslamination, and may have positive tone or negative tone to createcrosslinked and non-crosslinked portions using ultraviolet forpatterning conductive material layer. Non-crosslinked portions dissolveto form openings where conductive material may be deposited.

The finished substrate may be a single package substrate or may be arepeating unit that may undergo a singulation process in which each unitis separated for one another to create a single package substrate.Singulated substrates may be any suitable size and any suitablethickness; typically, substrates may be 50 mm by 50 mm in size, andbetween 100 um and 2000 um in thickness.

FIGS. 13A-B are a flow diagram of an example method of manufacturing apackage substrate including a high-density interconnect layer forscaling interconnects, in accordance with various embodiments. Althoughthe various operations discussed with reference to the method are shownin a particular order, the operations may be performed in any suitableorder (e.g., in any combination of parallel or series performance), andmay be repeated or omitted as suitable.

At 1302, a first metal layer may be provided on a carrier. For example,a copper foil layer 104 may be laminated on a temporary carrier 102.

At 1304, a second metal layer may be provided on the first metal layer.For example, a nickel layer 106 may be plated or laminated on the copperfoil layer 104.

At 1306, a seed layer may be provided on the second metal layer. Forexample, a copper seed layer 108 may be sputtered onto the nickel layer106.

At 1308, the high-density layer may be formed. For example, photoresistmay be applied to the top metal layer on the carrier, the high-densitymay be lithographically patterned, and copper traces may be platedfollowing the patterning.

At 1310, self-aligned pillars and vias may be formed on the high-densitylayer as described below in FIGS. 22-28. Once pillars and vias areformed, all photoresist may be removed.

At 1312, an adhesion promoter and dielectric layer may be provided onthe patterned conductive traces and vias. For example, the exposedcopper traces and vias of the high-density layer may be treated with anadhesion promoter and a dielectric layer may be laminated over thehigh-density layer.

At 1314, the top surface of the vias may be revealed by etching orplanarizing dielectric layer.

At 1316, the package substrate build up process may be performed to formmultiple layers of conductive traces and vias. The package substratebuild up process may be performed to route signals according towell-known design rules (e.g. 10/10 um L/S and 50 um via) after thehigh-density interconnect layer has been used to fan out the bump pitchfrom fine to course (e.g. 40 um BP to 110 um BP). At 1318, after thepackage substrate build up process is complete, the package substratemay be removed from the carrier, and the first and second metal layersmay be removed, for example, by chemical etching.

At 1320, the exposed copper surface may be finished by applying anadhesion promoter, laminating a dielectric layer, exposing the topsurface of the pillars, and applying a surface finish for die attachmentto the pillars.

In some embodiments, cavities for embedding and attaching dies to thescaled interconnects are provided. For example, a memory die with 40 umBP may be fanned out using the high-density layer, then routed usingstandard package substrate design rules to the logic die attached in thecavity. Since the logic die has a larger bump pitch, space on thehigh-density layer may be conserved by placing the logic die in a cavitywhich follows standard package substrate design rules. Additionally, byplacing the die in a cavity, the x/y dimensions of the substrate arereduced as well as the cost of production.

FIGS. 14-20 are cross-sectional side views of various stages in themanufacture of a package substrate including a high-density layer forscaling interconnects and an integrated die cavity, in accordance withvarious embodiments. In FIGS. 14-20, substrate formation is still beingperformed on both sides of the carrier, however, for a clearerillustration, the bottom side has been omitted from the figure.

FIG. 14 illustrates assembly 1400 subsequent to continuing the packagesubstrate build up process on assembly 900. In FIG. 14, the build upprocess is continued as necessary to scale interconnects. When the buildup process is complete for a particular fan out, a dielectric layer 1404may be deposited over the top conductive layer 1402.

FIG. 15 illustrates assembly 1500 subsequent to forming vias 1502 indielectric layer 1404 of assembly 1400. Vias may be formed by anysuitable process, such as by laser drilling, desmearing, andelectrolytic plating.

FIG. 16 illustrates assembly 1600 subsequent to planarizing anddepositing an etch stop material 1602 to the top surface of vias 1502 ofassembly 1500. The etch stop material may be any suitable material, suchas tin, and may be applied by any suitable process, such as immersion.

FIG. 17 illustrates assembly 1700 subsequent to continuing the build upprocess of assembly 1600 to finish the substrate through surface finishand to create a cavity 1702, and may include a temporary metal pad 1710(e.g., copper pad) that may act as a stop point for drilling whenopening the cavity as described below. Finishing of the back side, asdescribed previously, may include depositing an adhesion promoter,laminating dielectric, and exposing the top surface of the vias forattachment to a circuit board, or other board. Dielectric lamination,via formation, and via exposure may be performed as described previouslyfor the high-density layer in FIGS. 6 and 7. Finishing may also includeapplying solder resist 1704. In some embodiments, a surface finish 1706may be applied, such as an electroless metal or patterned copper, aswell as an etch stop material 1708, such as immersion tin or nickel.

FIG. 18 illustrates assembly 1800 subsequent to opening the cavity 1802of assembly 1700. The cavity may be opened by any suitable means,including laser drill, sandblasting, and wet/dry etching of thedielectric build up material.

FIG. 19 illustrates assembly 1900 subsequent to selectively etching thetemporary copper pad from the open cavity 1902 in the package substrate.For example, immersion tin may act as an etch stop as etch solutionselectivity for tin to copper is >1000:1, such that the temporary copperpad may be removed. Additionally, the temporary copper pad may act as astop for cavity drilling when opening the cavity. The advantage of usingthe etch stop is that routing may be allowed underneath and through thecavity.

FIG. 20 illustrates assembly 2000, which is assembly 1900 subsequent toseparating the assembly from the carrier and finishing the active side,as described above with reference to FIGS. 11-12.

FIG. 21 is a flow diagram of an example method of manufacturing apackage substrate including a high-density interconnect layer forscaling interconnects and an integrated die cavity as shown in FIGS.14-20, in accordance with various embodiments.

At 2102, a high-density layer may be formed on a coreless carrier andthe build up process may begin. Additionally, pillars and vias may beformed on the high-density layer. At 2104, the build up process may becontinued to fan out routing as necessary. At 2106, package substratevias may be formed and planarized on the top surface. At 2108, etch stopmaterial may be deposited on the top surface of the planarized vias. At2110, the build up process may be continued and a cavity with atemporary metal pad may be formed. At 2112, the build up process may befinished and the cavity may be opened. At 2114, the temporary metal padmay be removed. At 2116, the substrate assembly may be removed from thecarrier and the active side may be finished.

FIGS. 22-27 illustrate an example process flow for the formation ofself-aligned pillars based on a coreless high-density layer.Self-alignment may result in smaller pads than are typically available.These smaller pads may be used to increase the 10 density by having morerouting traces and/or to decrease the bump pitch.

FIG. 22A shows a plan view of a carrier layer with foil layers formedover the surfaces in an example method of manufacturing a self-alignedpillar in a package substrate including a high-density interconnectlayer, in accordance with various embodiments. FIGS. 22B-C show twocorresponding cross-sectional views of a carrier layer with foil layersformed over the surfaces. Although the figures show this process as atwo-sided process, the process may be performed on a single side of thecarrier. Further, although the figures show the formation of one pillar,one or more pillars may be formed at the same time or the process may berepeated for a single pillar to form additional pillars.

Referring to FIGS. 22B-C, a first metal layer 2204 (e.g., copper) may bedeposited over a top and bottom surface of a carrier substrate 2202. Thefirst metal layer 2204 may be any suitable metal, including nickel, tin,or copper, among others. The first metal layer 2204 may be any suitablemetal, including nickel, tin, or copper, among others. A second metallayer 2206 (e.g., nickel) may be deposited over the first metal layer2204. Optionally, the second metal layer may be covered with a sputteredor electroless copper layer (not shown) to improve adhesion to aphotoresist layer.

FIG. 23A shows a plan view of the carrier layer after a firstphotoresist layer has been patterned over the surfaces, in accordancewith various embodiments. FIGS. 23B-C show two correspondingcross-sectional views of the carrier layer after a first photoresistlayer has been patterned over the surfaces.

Referring to FIGS. 23B-C, a first photoresist layer 2302 may be formedover the second metal layer 2206, patterned to provide openings forhigh-density conductive lines, and plated with copper to form thehigh-density conductive lines 2304. The first photoresist layer may bepatterned using lithographic patterning processes (e.g., exposed withradiation source through a routing layer mask and developed with adeveloper), or any other suitable process. The high-density conductivelines may form a high-density layer (e.g., 2/2 um L/S and 14 um pad).The high-density conductive lines 2304 may be formed with electrolyticcopper plating, copper sputtering, or the like.

FIG. 24A shows a plan view of the carrier layer after a secondphotoresist layer has been patterned over the surfaces, in accordancewith various embodiments. FIGS. 24B-C show two correspondingcross-sectional views of the carrier layer after a second photoresistlayer has been patterned over the surfaces.

Referring to FIGS. 24B-C, a second photoresist layer 2402 may be formedover the first photoresist layer 2302 and conductive lines 2304, andpatterned to provide a pillar opening 2404. As shown in FIGS. 24B-C,three of the four walls of the pillar opening 2404 are defined by thefirst photoresist layer 2302 and the fourth wall is defined by thesecond photoresist layer 2402.

FIG. 25A shows a plan view of the carrier layer after exposed metalportions have been etched, in accordance with various embodiments. FIGS.25B-C shows two corresponding cross-sectional views of the carrier layerafter exposed metal portions have been etched.

Referring to FIGS. 25B-C, the exposed copper in the pillar opening maybe removed by, for example, subtractive etching solution with a highetch factor to minimize the expansion of the etch into the lines.Subsequent to removing the copper, a selective etch for the second metallayer 2206 (e.g., nickel layer) may be applied to remove the secondmetal layer in the pillar opening 2502. Nickel etching solutions withselectivity of 10:1 over copper are known in the art. For example, ifthe nickel metal layer is approximately 5 um thick, only approximately500 nm of the copper will be etched as well. Further, first metal layer2204 (i.e., copper layer) may act as an etch stop.

FIG. 26A shows a plan view of the carrier layer after metal has beenplated to fill the pillar, in accordance with various embodiments. FIGS.26B-C shows two corresponding cross-sectional views of the carrier layerafter metal has been plated to fill the pillar.

Referring to FIGS. 26B-C, after etching, the pillar opening 2602 may bereplated with copper up to the level of the copper line 2304, forexample, approximately, 7 um thick. The copper may be replated using anysuitable process, such as, electroless or electrolytic plating. However,the plating process should be controlled to deposit the copper to avoidoverfilling and impinging on the next layer of dielectric, which mayhave a thickness of approximately 3 um. The desired tolerance for copperplating thickness is ±30%.

FIG. 27A shows a plan view of the carrier layer after the secondphotoresist layer has been removed, in accordance with variousembodiments. FIGS. 27B-C show two corresponding cross-sectional views ofthe carrier layer after the second photoresist layer has been removed.

Referring to FIGS. 27B-C, the second photoresist layer 2402 may beremoved while leaving the first photoresist layer 2302 in place. Ifself-aligned vias are being formed, the second photoresist layer shouldbe removed without removing the first photoresist layer. In someembodiments, the first photoresist layer 2302 may be a permanentphotoreactive material that will not be stripped when the secondphotoresist layer is removed. In some embodiments, the first photoresistlayer may be protected by a copper (or other metal) seed layer. In someembodiments, where self-aligned vias are not being formed, the firstphotoresist layer may be removed.

The process for forming self-aligned vias on the high-density layer isthe same as shown in FIGS. 22-27 except that the etching process forremoving metal layers may be omitted. The second photoresist layer maybe patterned to form pillars and vias, or once the self-aligned pillarsare formed, the second photoresist layer may be removed, then reappliedand patterned to form self-aligned via openings. The openings may beplated to form self-aligned vias, and the second photoresist layer maybe removed.

As described above, when the build up process (i.e., SAP) is complete,the package substrate assembly may be separated from the temporarycarrier and the nickel metal layer may be etched away, for example,using the same selective etch solution used for pillar formation toreveal the copper pillars. A dielectric layer may be laminated over thecopper pillars. The top surface of the pillars subsequently may besubsequently revealed by a mechanical, chemical, or plasma etchback. Thepillars allow for the high-density interconnects to be covered bydielectric and increase the routing density on the high-density layer.

FIG. 28 is a flow diagram of an example method of forming self-alignedpillars and vias in a package substrate that includes a high-densityinterconnect layer, in accordance with various embodiments.

At 2802, a first metal layer (e.g., copper) may be deposited on acarrier. At 2804, a second metal layer (e.g., nickel) may be depositedover the first metal layer.

At 2806, a first photoresist layer may be deposited and patterned toform conductive line openings.

At 2808, a conductive material (e.g., copper) may be deposited in theopenings to form patterned conductive lines.

At 2810, a second photoresist layer may be deposited and patterned tocreate an opening for a pillar or, at 2811, a second photoresist layermay be deposited and patterned to create an opening for a via. Thepillar and via openings may be formed by the first and secondphotoresist layers.

At 1812, for pillar formation, the pillar opening may be etched toselectively remove the conductive line, then etched to selectivelyremove the second metal layer. Etching is not necessary for viaformation and may be omitted.

At 2814, conductive material (e.g., copper) may be deposited into thepillar opening to form a pillar and, at 2813, in the via opening to forma via. The pillar opening may be plated with conductive material, suchthat the conductive material of the pillar is approximately level withthe conductive lines. The via opening may be plated with conductivematerial to form a connection to the next conductive layer.

At 2816, once pillar(s) and via(s) are formed, the second photoresistlayer may be removed.

Additional pillars and vias may be formed on the high-density layer byrepeating the process for each as described starting at 2810, or bypatterning the photoresist layers for additional pillars and/or vias. At2818, once pillar formation and via formation on the high-densityinterconnect layer is complete, the first photoresist layer may beremoved.

The package substrates disclosed herein may be included in any suitableelectronic device. FIGS. 29-32 illustrate various examples ofapparatuses that may be included in, or that may include, one or more ofany of the package substrates disclosed herein.

FIGS. 29A-B are top views of a wafer 2900 and dies 2902 that may takethe form of any of the embodiments of the IC structures disclosedherein. The wafer 2900 may be composed of semiconductor material and mayinclude one or more dies 2902 having IC elements formed on a surface ofthe wafer 2900. Each of the dies 2902 may be a repeating unit of asemiconductor product that includes any suitable IC. After thefabrication of the semiconductor product is complete, the wafer 2900 mayundergo a singulation process in which each of the dies 2902 isseparated from one another to provide discrete “chips” of thesemiconductor product. The die 2902 may include one or more transistors(e.g., some of the transistors 3040 of FIG. 30, discussed below) and/orsupporting circuitry to route electrical signals to the transistors, aswell as any other IC components. The die 2902 may include one or moreconductive pathways. In some embodiments, the wafer 2900 or the die 2902may include a memory device (e.g., a static random access memory (SRAM)device), a logic device (e.g., an AND, OR, NAND, or NOR gate), or anyother suitable circuit element. Multiple ones of these devices may becombined on a single die 2902. For example, a memory array formed bymultiple memory devices may be formed on a same die 2902 as a processingdevice (e.g., the processing device 3202 of FIG. 32) or other logic thatis configured to store information in the memory devices or executeinstructions stored in the memory array.

FIG. 30 is a cross-sectional side view of an IC device 3000 that may beused with any of the embodiments of the IC structures disclosed herein.The IC device 3000 may be formed on a substrate 3002 (e.g., the wafer2900 of FIG. 29A) and may be included in a die (e.g., the die 2902 ofFIG. 29B). The substrate 3002 may be a semiconductor substrate composedof semiconductor material systems including, for example, N-type orP-type materials systems. The substrate 3002 may include, for example, acrystalline substrate formed using a bulk silicon or asilicon-on-insulator substructure. In some embodiments, the substrate3002 may be formed using alternative materials, which may or may not becombined with silicon, that include but are not limited to germanium,indium antimonide, lead telluride, indium arsenide, indium phosphide,gallium arsenide, or gallium antimonide. Further materials classified asgroup II-VI, III-V, or IV may also be used to form the substrate 3002.Although a few examples of materials from which the substrate 3002 maybe formed are described here, any material that may serve as afoundation for an IC device 3000 may be used. The substrate 3002 may bepart of a singulated die (e.g., the dies 2902 of FIG. 29B) or a wafer(e.g., the wafer 2900 of FIG. 29A).

The IC device 3000 may include one or more device layers 3004 disposedon the substrate 3002. The device layer 3004 may be included in thecircuitry at the device side of the die of the IC structures disclosedherein. The device layer 3004 may include features of one or moretransistors 3040 (e.g., metal oxide semiconductor field-effecttransistors (MOSFETs)) formed on the substrate 3002. The device layer3004 may include, for example, one or more source and/or drain (S/D)regions 3020, a gate 3022 to control current flow in the transistors3040 between the S/D regions 3020, and one or more S/D contacts 3024 toroute electrical signals to/from the S/D regions 3020. The transistors3040 may include additional features not depicted for the sake ofclarity, such as device isolation regions, gate contacts, and the like.The transistors 3040 are not limited to the type and configurationdepicted in FIG. 30 and may include a wide variety of other types andconfigurations such as, for example, planar transistors, nonplanartransistors, or a combination of both. Nonplanar transistors may includeFinFET transistors, such as double-gate transistors or tri-gatetransistors, and wraparound or all-around gate transistors, such asnanoribbon and nanowire transistors.

Each transistor 3040 may include a gate 3022 formed of at least twolayers, a gate dielectric layer and a gate electrode layer. The gatedielectric layer may include one layer or a stack of layers. The one ormore layers may include silicon oxide, silicon dioxide, and/or a high-kdielectric material. The high-k dielectric material may include elementssuch as hafnium, silicon, oxygen, titanium, tantalum, lanthanum,aluminum, zirconium, barium, strontium, yttrium, lead, scandium,niobium, and zinc.

Examples of high-k materials that may be used in the gate dielectriclayer include, but are not limited to, hafnium oxide, hafnium siliconoxide, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide,zirconium silicon oxide, tantalum oxide, titanium oxide, bariumstrontium titanium oxide, barium titanium oxide, strontium titaniumoxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, andlead zinc niobate. In some embodiments, an annealing process may becarried out on the gate dielectric layer to improve its quality when ahigh-k material is used.

The gate electrode layer may be formed on the gate dielectric layer andmay include at least one P-type work-function metal or N-typework-function metal, depending on whether the transistor 3040 is to be aPMOS or an NMOS transistor. In some implementations, the gate electrodelayer may consist of a stack of two or more metal layers, where one ormore metal layers are work-function metal layers and at least one metallayer is a fill metal layer. Further metal layers may be included forother purposes, such as a barrier layer. For a PMOS transistor, metalsthat may be used for the gate electrode include, but are not limited to,ruthenium, palladium, platinum, cobalt, nickel, and conductive metaloxides (e.g., ruthenium oxide). For an NMOS transistor, metals that maybe used for the gate electrode include, but are not limited to, hafnium,zirconium, titanium, tantalum, aluminum, alloys of these metals, andcarbides of these metals (e.g., hafnium carbide, zirconium carbide,titanium carbide, tantalum carbide, and aluminum carbide).

In some embodiments, when viewed as a cross section of the transistor3040 along the source-channel-drain direction, the gate electrode mayconsist of a U-shaped structure that includes a bottom portionsubstantially parallel to the surface of the substrate and two sidewallportions that are substantially perpendicular to the top surface of thesubstrate. In other embodiments, at least one of the metal layers thatform the gate electrode may simply be a planar layer that issubstantially parallel to the top surface of the substrate and does notinclude sidewall portions substantially perpendicular to the top surfaceof the substrate. In other embodiments, the gate electrode may consistof a combination of U-shaped structures and planar, non-U-shapedstructures. For example, the gate electrode may consist of one or moreU-shaped metal layers formed atop one or more planar, non-U-shapedlayers.

In some embodiments, a pair of sidewall spacers may be formed onopposing sides of the gate stack to bracket the gate stack. The sidewallspacers may be formed from a material such as silicon nitride, siliconoxide, silicon carbide, silicon nitride doped with carbon, and siliconoxynitride. Processes for forming sidewall spacers are well known in theart and generally include deposition and etching process steps. In someembodiments, a plurality of spacer pairs may be used; for instance, twopairs, three pairs, or four pairs of sidewall spacers may be formed onopposing sides of the gate stack.

The S/D regions 3020 may be formed within the substrate 3002 adjacent tothe gate 3022 of each transistor 3040. The S/D regions 3020 may beformed using either an implantation/diffusion process or anetching/deposition process, for example. In the former process, dopantssuch as boron, aluminum, antimony, phosphorous, or arsenic may beion-implanted into the substrate 3002 to form the S/D regions 3020. Anannealing process that activates the dopants and causes them to diffusefarther into the substrate 3002 may follow the ion-implantation process.In the latter process, the substrate 3002 may first be etched to formrecesses at the locations of the S/D regions 3020. An epitaxialdeposition process may then be carried out to fill the recesses withmaterial that is used to fabricate the S/D regions 3020. In someimplementations, the S/D regions 3020 may be fabricated using a siliconalloy such as silicon germanium or silicon carbide. In some embodiments,the epitaxially deposited silicon alloy may be doped in situ withdopants such as boron, arsenic, or phosphorous. In some embodiments, theS/D regions 3020 may be formed using one or more alternate semiconductormaterials such as germanium or a group III-V material or alloy. Infurther embodiments, one or more layers of metal and/or metal alloys maybe used to form the S/D regions 3020.

Electrical signals, such as power and/or input/output (I/O) signals, maybe routed to and/or from the transistors 3040 of the device layer 3004through one or more interconnect layers disposed on the device layer3004 (illustrated in FIG. 30 as interconnect layers 3006-3010), whichmay be any of the embodiments of the IC structures disclosed herein. Forexample, electrically conductive features of the device layer 3004(e.g., the gate 3022 and the S/D contacts 3024) may be electricallycoupled with the interconnect structures 3028 of the interconnect layers3006-3010. The one or more interconnect layers 3006-3010 may form aninterlayer dielectric (ILD) stack 3019 of the IC device 3000. Theconductive pathways 3012 may extend to, and electrically couple to, oneor more of the interconnect layers 3006-3010. The conductive pathways3012 may route signals to/from the devices in the device layer 3004, ormay route signals through the interconnect layers 3006-3010 to/fromother devices (e.g., other electronic components in a stacked ICstructure, or other components sharing a circuit board with the ICdevice 3000).

The interconnect structures 3028 may be arranged within the interconnectlayers 3006-3010 to route electrical signals according to a wide varietyof designs (in particular, the arrangement is not limited to theparticular configuration of interconnect structures 3028 depicted inFIG. 30). Although a particular number of interconnect layers 3006-3010is depicted in FIG. 30, embodiments of the present disclosure include ICdevices having more or fewer interconnect layers than depicted.

In some embodiments, the interconnect structures 3028 may include trenchstructures 3028 a (sometimes referred to as “lines”) and/or viastructures 3028 b (sometimes referred to as “holes”) filled with anelectrically conductive material such as a metal. The trench structures3028 a may be arranged to route electrical signals in a direction of aplane that is substantially parallel with a surface of the substrate3002 upon which the device layer 3004 is formed. For example, the trenchstructures 3028 a may route electrical signals in a direction in and outof the page from the perspective of FIG. 30. The via structures 3028 bmay be arranged to route electrical signals in a direction of a planethat is substantially perpendicular to the surface of the substrate 3002upon which the device layer 3004 is formed. In some embodiments, the viastructures 3028 b may electrically couple trench structures 3028 a ofdifferent interconnect layers 3006-3010 together.

The interconnect layers 3006-3010 may include a dielectric material 3026disposed between the interconnect structures 3028, as shown in FIG. 30.In some embodiments, the dielectric material 3026 disposed between theinterconnect structures 3028 in different ones of the interconnectlayers 3006-3010 may have different compositions; in other embodiments,the composition of the dielectric material 3026 between differentinterconnect layers 3006-3010 may be the same.

A first interconnect layer 3006 (referred to as Metal 1 or “M1”) may beformed directly on the device layer 3004. In some embodiments, the firstinterconnect layer 3006 may include trench structures 3028 a and/or viastructures 3028 b, as shown. The trench structures 3028 a of the firstinterconnect layer 3006 may be coupled with contacts (e.g., the S/Dcontacts 3024) of the device layer 3004.

A second interconnect layer 3008 (referred to as Metal 2 or “M2”) may beformed directly on the first interconnect layer 3006. In someembodiments, the second interconnect layer 3008 may include viastructures 3028 b to couple the trench structures 3028 a of the secondinterconnect layer 3008 with the trench structures 3028 a of the firstinterconnect layer 3006. Although the trench structures 3028 a and thevia structures 3028 b are structurally delineated with a line withineach interconnect layer (e.g., within the second interconnect layer3008) for the sake of clarity, the trench structures 3028 a and the viastructures 3028 b may be structurally and/or materially contiguous(e.g., simultaneously filled during a dual-damascene process) in someembodiments.

A third interconnect layer 3010 (referred to as Metal 3 or “M3”) (andadditional interconnect layers, as desired) may be formed in successionon the second interconnect layer 3008 according to similar techniquesand configurations described in connection with the second interconnectlayer 3008 or the first interconnect layer 3006.

The IC device 3000 may include a solder resist material 3034 (e.g.,polyimide or similar material) and one or more bond pads 3036 formed onthe interconnect layers 3006-3010. The bond pads 3036 may provide thecontacts to couple to the FLI, for example. The bond pads 3036 may beelectrically coupled with the interconnect structures 3028 andconfigured to route the electrical signals of the transistor(s) 3040 toother external devices. For example, solder bonds may be formed on theone or more bond pads 3036 to mechanically and/or electrically couple achip including the IC device 3000 with another component (e.g., acircuit board). The IC device 3000 may have other alternativeconfigurations to route the electrical signals from the interconnectlayers 3006-3010 than depicted in other embodiments. For example, thebond pads 3036 may be replaced by or may further include other analogousfeatures (e.g., posts) that route the electrical signals to externalcomponents.

FIG. 31 is a cross-sectional side view of an IC device assembly 3100that may include any of the embodiments of the IC structures disclosedherein. The IC device assembly 3100 includes a number of componentsdisposed on a circuit board 3102 (which may be, e.g., a motherboard).The IC device assembly 3100 includes components disposed on a first face3140 of the circuit board 3102 and an opposing second face 3142 of thecircuit board 3102; generally, components may be disposed on one or bothfaces 3140 and 3142.

In some embodiments, the circuit board 3102 may be a printed circuitboard (PCB) including multiple metal layers separated from one anotherby layers of dielectric material and interconnected by electricallyconductive vias. Any one or more of the metal layers may be formed in adesired circuit pattern to route electrical signals (optionally inconjunction with other metal layers) between the components coupled tothe circuit board 3102. In other embodiments, the circuit board 3102 maybe a non-PCB substrate.

The IC device assembly 3100 illustrated in FIG. 31 includes apackage-on-interposer structure 3136 coupled to the first face 3140 ofthe circuit board 3102 by coupling components 3116. The couplingcomponents 3116 may electrically and mechanically couple thepackage-on-interposer structure 3136 to the circuit board 3102, and mayinclude solder balls (as shown in FIG. 31), male and female portions ofa socket, an adhesive, an underfill material, and/or any other suitableelectrical and/or mechanical coupling structure.

The package-on-interposer structure 3136 may include an electronicspackage 3120 coupled to an interposer 3104 by coupling components 3118.The coupling components 3118 may take any suitable form for theapplication, such as the forms discussed above with reference to thecoupling components 3116. Although a single electronics package 3120 isshown in FIG. 31, multiple electronics packages may be coupled to theinterposer 3104; indeed, additional interposers may be coupled to theinterposer 3104. The interposer 3104 may provide an interveningsubstrate used to bridge the circuit board 3102 and the electronicspackage 3120. The electronics package 3120 may be or include, forexample, a die (the die 2902 of FIG. 29B), an IC device (e.g., the ICdevice 3000 of FIG. 30), or any other suitable component. Generally, theinterposer 3104 may spread a connection to a wider pitch or reroute aconnection to a different connection. For example, the interposer 3104may couple the electronics package 3120 (e.g., a die) to a ball gridarray (BGA) of the coupling components 3116 for coupling to the circuitboard 3102. In the embodiment illustrated in FIG. 31, the electronicspackage 3120 and the circuit board 3102 are attached to opposing sidesof the interposer 3104; in other embodiments, the electronics package3120 and the circuit board 3102 may be attached to a same side of theinterposer 3104. In some embodiments, three or more components may beinterconnected by way of the interposer 3104. In some embodiments, theelectronics package 3120 may include an IC structure disclosed herein.An additional electronic component may be disposed on the electronicspackage 3120 to form a stacked IC structure.

The interposer 3104 may be formed of an epoxy resin, afiberglass-reinforced epoxy resin, a ceramic material, or a polymermaterial such as polyimide. In some embodiments, the interposer 3104 maybe formed of alternate rigid or flexible materials that may include thesame materials described above for use in a semiconductor substrate,such as silicon, germanium, and other group III-V and group IVmaterials. The interposer 3104 may include metal interconnects 3108 andvias 3110, including but not limited to through-silicon vias (TSVs)3106. The interposer 3104 may further include embedded devices 3114,including both passive and active devices. Such devices may include, butare not limited to, capacitors, decoupling capacitors, resistors,inductors, fuses, diodes, transformers, sensors, electrostatic discharge(ESD) devices, and memory devices. More complex devices such asradio-frequency (RF) devices, power amplifiers, power managementdevices, antennas, arrays, sensors, and microelectromechanical systems(MEMS) devices may also be formed on the interposer 3104. Thepackage-on-interposer structure 3136 may take the form of any of thepackage-on-interposer structures known in the art.

The IC device assembly 3100 may include an electronics package 3124coupled to the first face 3140 of the circuit board 3102 by couplingcomponents 3122. The coupling components 3122 may take the form of anyof the embodiments discussed above with reference to the couplingcomponents 3116, and the electronics package 3124 may take the form ofany of the embodiments discussed above with reference to the electronicspackage 3120. In some embodiments, the electronics package 3124 mayinclude any IC structure disclosed herein. An additional electroniccomponent may be disposed on the electronics package 3124 to form astacked IC structure.

The IC device assembly 3100 illustrated in FIG. 31 includes apackage-on-package structure 3134 coupled to the second face 3142 of thecircuit board 3102 by coupling components 3128. The package-on-packagestructure 3134 may include an electronics package 3126 and anelectronics package 3132 coupled together by coupling components 3130such that the electronics package 3126 is disposed between the circuitboard 3102 and the electronics package 3132. The package-on-packagestructure 3134 may take the form of an IC structure disclosed herein.The coupling components 3128 and 3130 may take the form of any of theembodiments of the coupling components 3116 discussed above, and theelectronics packages 3126 and 3132 may take the form of any of theembodiments of the electronics package 3120 discussed above.

FIG. 32 is a block diagram of an example computing device 3200 that mayinclude one or more of any of the embodiments of the IC structuresdisclosed herein. A number of components are illustrated in FIG. 32 asincluded in the computing device 3200, but any one or more of thesecomponents may be omitted or duplicated, as suitable for theapplication. In some embodiments, some or all of the components includedin the computing device 3200 may be attached to one or moremotherboards. In some embodiments, some or all of these components arefabricated onto a single system-on-a-chip (SoC) die.

Additionally, in various embodiments, the computing device 3200 may notinclude one or more of the components illustrated in FIG. 32, but thecomputing device 3200 may include interface circuitry for coupling tothe one or more components. For example, the computing device 3200 maynot include a display device 3206, but may include display deviceinterface circuitry (e.g., a connector and driver circuitry) to which adisplay device 3206 may be coupled. In another set of examples, thecomputing device 3200 may not include an audio input device 3224 or anaudio output device 3208, but may include audio input or output deviceinterface circuitry (e.g., connectors and supporting circuitry) to whichan audio input device 3224 or audio output device 3208 may be coupled.

The computing device 3200 may include a processing device 3202 (e.g.,one or more processing devices). As used herein, the term “processingdevice” or “processor” may refer to any device or portion of a devicethat processes electronic data from registers and/or memory to transformthat electronic data into other electronic data that may be stored inregisters and/or memory. The processing device 3202 may include one ormore digital signal processors (DSPs), application-specific integratedcircuits (ASICs), central processing units (CPUs), graphics processingunits (GPUs), cryptoprocessors (specialized processors that executecryptographic algorithms within hardware), server processors, or anyother suitable processing devices. The computing device 3200 may includea memory 3204, which may itself include one or more memory devices suchas volatile memory (e.g., dynamic random access memory (DRAM)),nonvolatile memory (e.g., read-only memory (ROM)), flash memory, solidstate memory, and/or a hard drive. In some embodiments, the memory 3204may include memory that shares a die with the processing device 3202.This memory may be used as cache memory and may include embedded dynamicrandom access memory (eDRAM) or spin transfer torque magneticrandom-access memory (STT-M RAM).

In some embodiments, the computing device 3200 may include acommunication chip 3212 (e.g., one or more communication chips). Forexample, the communication chip 3212 may be configured for managingwireless communications for the transfer of data to and from thecomputing device 3200. The term “wireless” and its derivatives may beused to describe circuits, devices, systems, methods, techniques,communications channels, etc., that may communicate data through the useof modulated electromagnetic radiation through a nonsolid medium. Theterm does not imply that the associated devices do not contain anywires, although in some embodiments they might not.

The communication chip 3212 may implement any of a number of wirelessstandards or protocols, including but not limited to Institute forElectrical and Electronic Engineers (IEEE) standards including Wi-Fi(IEEE 802.11 family), IEEE 802.16 standards (e.g., IEEE 802.16-2005Amendment), Long-Term Evolution (LTE) project along with any amendments,updates, and/or revisions (e.g., advanced LTE project, ultra-mobilebroadband (UMB) project (also referred to as “3GPP2”), etc.). IEEE802.16 compatible Broadband Wireless Access (BWA) networks are generallyreferred to as WiMAX networks, an acronym that stands for WorldwideInteroperability for Microwave Access, which is a certification mark forproducts that pass conformity and interoperability tests for the IEEE802.16 standards. The communication chip 3212 may operate in accordancewith a Global System for Mobile Communication (GSM), General PacketRadio Service (GPRS), Universal Mobile Telecommunications System (UMTS),High Speed Packet Access (HSPA), Evolved HSPA (E-HSPA), or LTE network.The communication chip 3212 may operate in accordance with Enhanced Datafor GSM Evolution (EDGE), GSM EDGE Radio Access Network (GERAN),Universal Terrestrial Radio Access Network (UTRAN), or Evolved UTRAN(E-UTRAN). The communication chip 3212 may operate in accordance withCode Division Multiple Access (CDMA), Time Division Multiple Access(TDMA), Digital Enhanced Cordless Telecommunications (DECT),Evolution-Data Optimized (EV-DO), and derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The communication chip 3212 may operate in accordance with otherwireless protocols in other embodiments. The computing device 3200 mayinclude an antenna 3222 to facilitate wireless communications and/or toreceive other wireless communications (such as AM or FM radiotransmissions).

In some embodiments, the communication chip 3212 may manage wiredcommunications, such as electrical, optical, or any other suitablecommunication protocols (e.g., the Ethernet). As noted above, thecommunication chip 3212 may include multiple communication chips. Forinstance, a first communication chip 3212 may be dedicated toshorter-range wireless communications such as Wi-Fi or Bluetooth, and asecond communication chip 3212 may be dedicated to longer-range wirelesscommunications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE, EV-DO, orothers. In some embodiments, a first communication chip 3212 may bededicated to wireless communications, and a second communication chip3212 may be dedicated to wired communications.

The computing device 3200 may include battery/power circuitry 3214. Thebattery/power circuitry 3214 may include one or more energy storagedevices (e.g., batteries or capacitors) and/or circuitry for couplingcomponents of the computing device 3200 to an energy source separatefrom the computing device 3200 (e.g., AC line power).

The computing device 3200 may include a display device 3206 (orcorresponding interface circuitry, as discussed above). The displaydevice 3206 may include any visual indicators, such as a heads-updisplay, a computer monitor, a projector, a touchscreen display, aliquid crystal display (LCD), a light-emitting diode display, or a flatpanel display, for example.

The computing device 3200 may include an audio output device 3208 (orcorresponding interface circuitry, as discussed above). The audio outputdevice 3208 may include any device that generates an audible indicator,such as speakers, headsets, or earbuds, for example.

The computing device 3200 may include an audio input device 3224 (orcorresponding interface circuitry, as discussed above). The audio inputdevice 3224 may include any device that generates a signalrepresentative of a sound, such as microphones, microphone arrays, ordigital instruments (e.g., instruments having a musical instrumentdigital interface (MIDI) output).

The computing device 3200 may include a global positioning system (GPS)device 3218 (or corresponding interface circuitry, as discussed above).The GPS device 3218 may be in communication with a satellite-basedsystem and may receive a location of the computing device 3200, as knownin the art.

The computing device 3200 may include an other output device 3210 (orcorresponding interface circuitry, as discussed above). Examples of theother output device 3210 may include an audio codec, a video codec, aprinter, a wired or wireless transmitter for providing information toother devices, or an additional storage device.

The computing device 3200 may include an other input device 3220 (orcorresponding interface circuitry, as discussed above). Examples of theother input device 3220 may include an accelerometer, a gyroscope, acompass, an image capture device, a keyboard, a cursor control devicesuch as a mouse, a stylus, a touchpad, a bar code reader, a QuickResponse (QR) code reader, any sensor, or a radio frequencyidentification (RFID) reader.

The computing device 3200 may have any desired form factor, such as ahand-held or mobile computing device (e.g., a cell phone, a smart phone,a mobile internet device, a music player, a tablet computer, a laptopcomputer, a netbook computer, an ultrabook computer, a personal digitalassistant (PDA), an ultra-mobile personal computer, etc.), a desktopcomputing device, a server or other networked computing component, aprinter, a scanner, a monitor, a set-top box, an entertainment controlunit, a vehicle control unit, a digital camera, a digital videorecorder, or a wearable computing device. In some embodiments, thecomputing device 3200 may be any other electronic device that processesdata.

The following examples pertain to further embodiments. The variousfeatures of the different embodiments may be variously combined withsome features included and others excluded to suit a variety ofdifferent applications.

Example 1 is an integrated circuit package, including: a high-densityinterconnect layer having a first side and a second side; a pillarformed on the first side of the high-density interconnect layer; a viaformed on the second side of the high-density interconnect layer; afirst die; and a package substrate.

Example 2 may include the subject matter of Example 1, and may furtherspecify that the first die is electrically coupled to the pillar.

Example 3 may include the subject matter of Example 1, and may furtherspecify that the package substrate is electrically coupled to the via.

Example 4 may include the subject matter of any of Examples 1-3, and mayfurther include: a cavity formed on the package substrate.

Example 5 may include the subject matter of Example 4, and may furtherinclude: a second die in the cavity formed on the package substrate,wherein the second die is conductively connected to the packagesubstrate.

Example 6 may include the subject matter of Example 5, and may furtherinclude: a third die in the cavity formed on the package substrate,wherein the third die is conductively connected to the second die.

Example 7 may include the subject matter of Example 1, and may furtherspecify that the I/O of the high-density interconnect layer is between100-1000 I/O/mm/layer.

Example 8 may include the subject matter of Example 1, and may furtherspecify that the I/O of the package substrate is between 15-60I/O/mm/layer.

Example 9 may include the subject matter of Example 1, and may furtherspecify that a plurality of pillars is formed on the first side of thehigh-density interconnect layer, and that the bump pitch of the pillarsis between 10 um-80 um.

Example 10 may include the subject matter of Example 1, and may furtherspecify that the bump pitch on the back side of the package substrate isbetween 200 um-1000 um.

Example 11 may include the subject matter of Example 1, and may furtherspecify that the pad size on the high-density interconnect layer isbetween 1 um-24 um.

Example 12 may include the subject matter of Example 1, and may furtherspecify that the pillar on the high-density interconnect layer is aself-aligned pillar.

Example 13 may include the subject matter of Example 1, and may furtherspecify that the via on the high-density interconnect layer is aself-aligned via.

Example 14 is a method of forming an integrated circuit package, themethod including: depositing a first metal layer on a carrier;depositing a second metal layer over the first metal layer; forming ahigh-density interconnect layer over the second metal layer; forming apillar on the high-density interconnect layer; forming a via on thehigh-density interconnect layer; forming a package substrate; removingthe substrate from the carrier; etching the first and second metallayers to expose the pillar; and finishing the top and bottom surfacesof the package substrate.

Example 15 may include the subject matter of Example 14, and may furtherinclude: attaching a die to the active side, wherein the die iselectrically coupled to the pillar on the high-density interconnectlayer.

Example 16 may include the subject matter of any of Examples 14-15, andmay further specify that forming the package substrate further includes:forming a via in the package substrate; planarizing the top surface ofthe via; depositing an etch stop material on the top surface of the via;continuing the package substrate build up process forming a cavity; andopening the cavity.

Example 17 may include the subject matter of Example 16, and may furtherinclude: attaching a first die in the cavity, wherein the first die isconductively connected to the package substrate.

Example 18 may include the subject matter of Example 17, and may furtherinclude: attaching a second die in the cavity, wherein the second die isconductively connected to the first die.

Example 19 may include the subject matter of Example 14, and may furtherspecify that forming a high-density interconnect layer further includes:depositing and patterning a first photoresist layer to form openings forconductive lines; and plating metal in the openings to form conductivelines.

Example 20 may include the subject matter of Example 19, and may furtherspecify that the method of forming the pillar on the high-densityinterconnect layer further includes: depositing and patterning a secondphoto resist layer over the first photo resist layer and conductivelines to form an opening for the pillar; etching the pillar opening toremove the plated metal conductive line; etching the pillar opening toremove the second metal layer; replating metal in the opening to formthe pillar; and removing the second photoresist layer.

Example 21 may include the subject matter of Example 19, and may furtherspecify that the method of forming the via on the high-densityinterconnect layer further includes: depositing and patterning a secondphoto resist layer over the first photo resist layer and conductivelines to form an opening for a via; plating metal in the opening to formthe via; and removing the second photoresist layer.

Example 22 is a computing device, including: a circuit board; and anintegrated circuit package coupled to the circuit board, wherein theintegrated circuit package includes: a high-density interconnect layerhaving a first side and a second side; a pillar formed on the first sideof the high-density interconnect layer; a via formed on the second sideof the high-density interconnect layer; a first die; and a packagesubstrate.

Example 23 may include the subject matter of Example 22, and may furtherspecify that the first die is electrically coupled to the pillar.

Example 24 may include the subject matter of Example 22, and may furtherspecify that the package substrate is electrically coupled to the via.

Example 25 may include the subject matter of any of Examples 22-24, andmay further include: a cavity formed on the package substrate.

Example 26 may include the subject matter of Example 25, and may furtherinclude: a second die in the cavity formed on the package substrate,wherein the second die is conductively connected to the packagesubstrate.

Example 27 may include the subject matter of Example 26, and may furtherinclude: a third die in the cavity formed on the package substrate,wherein the third die is conductively connected to the second die.

Example 28 may include the subject matter of Example 22, and may furtherspecify that the I/O of the high-density interconnect layer is between100-1000 I/O/mm/layer.

Example 29 may include the subject matter of Example 22, and may furtherspecify that the I/O of the package substrate is between 15-60I/O/mm/layer.

Example 30 may include the subject matter of Example 22, and may furtherspecify that a plurality of pillars is formed on the first side of thehigh-density interconnect layer, and wherein the bump pitch of thepillars is between 10 um-80 um.

Example 31 may include the subject matter of Example 22, and may furtherspecify that the bump pitch on the back side of the package substrate isbetween 200 um-1000 um.

Example 32 may include the subject matter of Example 22, and may furtherspecify that the pad size on the high-density interconnect layer isbetween 1 um-24 um.

Example 33 may include the subject matter of Example 22, and may furtherspecify that the pillar on the high-density interconnect layer is aself-aligned pillar.

Example 34 may include the subject matter of Example 22, and may furtherspecify that the via on the high-density interconnect layer is aself-aligned via.

1-25. (canceled)
 26. An integrated circuit package, comprising: a package substrate having a first face and an opposing second face, wherein a bump pitch of the second face of the package substrate is between 200 um and 1000 um, and wherein the package substrate includes a plurality of layers; a high-density interconnect layer having a first side and an opposing second side, wherein the high-density interconnect layer is an individual layer of the plurality of layers at the first face of the package substrate, and wherein the high-density interconnect layer includes: a plurality of pillars formed on the first side of the high-density interconnect layer, wherein a bump pitch of the plurality of pillars is between 10 um and 80 um; and a via formed on the second side of the high-density interconnect layer, wherein a next individual layer of the plurality of layers of the package substrate is electrically coupled to the via; and a first die, wherein the first die is electrically coupled to an individual pillar of the plurality of pillars on the high-density interconnect layer.
 27. The integrated circuit package of claim 26, wherein a diameter of an individual pillar of the plurality of pillars is between 2 um and 20 um.
 28. The integrated circuit package of claim 26, wherein a diameter of the via is between 2 um and 10 um.
 29. The integrated circuit package of claim 26, further comprising: a cavity formed on the package substrate.
 30. The integrated circuit package of claim 29, further comprising: a second die in the cavity formed on the package substrate, wherein the second die is conductively connected to the package substrate.
 31. The integrated circuit package of claim 30, further comprising: a third die in the cavity formed on the package substrate, wherein the third die is conductively connected to the second die.
 32. The integrated circuit package of claim 26, wherein an input/output (I/O) of an individual layer of the plurality of layers of the package substrate that is not the high-density interconnect layer is between 15 and 60 I/O/mm/layer.
 33. The integrated circuit package of claim 26, wherein an I/O of the high-density interconnect layer is between 100 and 1000 I/O/mm/layer.
 34. A computing device, comprising: a circuit board; and an integrated circuit package coupled to the circuit board, wherein the integrated circuit package comprises: a package substrate having a first face and an opposing second face, wherein a bump pitch of the second face of the package substrate is between 200 um and 1000 um, and wherein the package substrate includes a plurality of layers; a high-density interconnect layer having a first side and an opposing second side, wherein the high-density interconnect layer is an individual layer of the plurality of layers of the package substrate and is at the first face of the package substrate, and wherein the high-density interconnect layer includes: a plurality of pillars formed on the first side of the high-density interconnect layer, wherein a bump pitch of the plurality of pillars is between 10 um and 80 um; and a via formed on the second side of the high-density interconnect layer, wherein a next individual layer of the plurality of layers of the package substrate is electrically coupled to the via; and a first die, wherein the first die is electrically coupled to the package substrate via one or more of the plurality of pillars on the high-density interconnect layer.
 35. The computing device of claim 34, wherein a diameter of an individual pillar of the plurality of pillars is between 2 um and 20 um.
 36. The computing device of claim 34, wherein a diameter of the via is between 2 um and 10 um.
 37. The computing device of claim 34, further comprising: a cavity formed on the package substrate.
 38. The computing device of claim 37, further comprising: a second die in the cavity formed on the package substrate, wherein the second die is conductively connected to the package substrate.
 39. The computing device of claim 38, further comprising: a third die in the cavity formed on the package substrate, wherein the third die is conductively connected to the second die.
 40. An integrated circuit assembly, comprising: a package substrate having a first face and an opposing second face, wherein a bump pitch of the second face of the package substrate is between 200 um and 1000 um, and wherein the package substrate includes a plurality of layers; and a high-density interconnect layer having a first side and an opposing second side, wherein the high-density interconnect layer is an individual layer of the plurality of layers of the package substrate at the first face of the package substrate, and wherein the high-density interconnect layer includes: a plurality of pillars formed on the first side of the high-density interconnect layer, wherein a bump pitch of the plurality of pillars is between 10 um and 80 um; and a via formed on the second side of the high-density interconnect layer, wherein a next individual layer of the plurality of layers of the package substrate is electrically coupled to the via.
 41. The integrated circuit assembly of claim 40, wherein an input/output (I/O) of an individual layer of the plurality of layers of the package substrate that is not the high-density interconnect layer is between 15 and 60 I/O/mm/layer.
 42. The integrated circuit assembly of claim 40, wherein an I/O of the high-density interconnect layer is between 100 and 1000 I/O/mm/layer.
 43. The integrated circuit assembly of claim 40, wherein a diameter of an individual pillar of the plurality of pillars is between 2 um and 20 um.
 44. The integrated circuit assembly of claim 40, wherein a diameter of the via is between 2 um and 10 um.
 45. The integrated circuit assembly of claim 40, wherein the high-density interconnect layer further includes a pad formed on the second side of the high-density interconnect layer and the pad has a pad size between 1 um and 24 um. 